The subject invention is directed toward the art of medical equipment and, more particularly, to a surgical smoke evacuation system with a unitary filter cartridge module that can be easily replaced and further, including filter usage circuit and display device that accurately shows actual filter usage and is easily readable by medical equipment operators.
The invention is especially well suited for incorporation into overhead surgical equipment management systems and will be described with particular reference thereto. However, as will become apparent, the invention is capable of broader application beyond surgical use and could be supported by and/or integrated into a variety of medical equipment apparatus such as, for example, surgical carts and free standing support stands, and further, could be integrated directly into medical operating room walls, ceilings, or floors, or the like.
It is well known that in many forms of laser surgery, orthopedic surgery, and electro-cauterization, smoke is generated including very fine particles of vaporized tissue, blood, and other bodily fluids sometimes mixed with liquids, bone fragments, and other larger sized debris. It is advantageous to the surgeon to not only remove these surgical by-products from the surgical site because they interfere with access to the surgical site, but also to rid the operating room of the by-products so that they are not inhaled or leaked into inappropriate areas. To that end, various tubular fluid suction apparatus have been proposed for removing liquids and large pieces such as bone fragments that are generated and accumulate within the surgical incision. In addition, a wide range of smoke evacuation systems have been proposed for removing finer airborne particles including smoke and other smaller debris that rises from the surgical site and into the air space of the operating room.
One such laser plume evacuation system is described in U.S. Pat. No. 5,409,511 to Paul. As taught there, an elongate section of tubing is carried from the surgical site to a vacuum source by an articulating arm assembly connected from overhead to the ceiling of the operating room. The Paul system proposes a single centrally located centrifugal separator tank, garbage pump, vacuum producer or fan, and HEPA filter, collectively "vacuum source". The vacuum source is sufficiently large to provide adequate air flow to enable multiple simultaneous surgeries to be performed in multiple independent surgical rooms. In that regard, the vacuum source is typically centrally located wherein each of the operating rooms is connected to the vacuum source by a system of tubing strings that are routed overhead through the surgical ceiling network.
One disadvantage of laser plume evacuation systems of the type described is that the filters are not easily replaceable by operating room personnel. The filters are neither modular nor are they located within the same room in which the surgical procedures are performed. Normally, the filters can only be serviced by trained technicians. This makes filter replacement difficult and expensive.
Another disadvantage of the prior art plume evacuation systems is that they offer a mostly inadequate representation of usable filter life remaining. This can compromise surgical procedures because of an inability to properly gauge the useful time remaining on any given filter at the vacuum source. Further, inadequate air flow can unknowingly result when the filter becomes clogged because of gage accuracy limitations.
Typically, filter status signals used in prior art plume evacuation systems are based on calculations derived from either a pressure differential signal or a strict timer value. Commonly, a pressure transducer is disposed adjacent or across the filter medium in order to sense a pressure differential developed between air flows upstream and downstream from the filter medium. As the filter becomes worn and clogged, the pressure differential developed across the filter increases. For that reason, pressure differential type systems are usually accurate only when used within a narrow range of air flow rates. Simple system changes, such as replacing a suction hose with another having a different length or diameter, can result in completely inaccurate pressure differential readings.
Alternatively, absolute counters or timers have been proposed to essentially log total filter usage. The counter or timer is reset whenever the filters are replaced. However, much of the usable filter life is usually wasted because the timers are typically set to expire prematurely based on a "worst case" usage estimate. The counters are almost completely inaccurate when the vacuum system is used outside of its normal flow rate range of operation and when system parameters are changed such as with hose replacement as noted above.
It would therefore be desirable to provide a surgical smoke evacuation system that enables easy filter replacement by personnel in the operating room.
It would also be desirable to provide a replaceable pre-filter assembly including an elongate suction hose segment and a pre-filter housing for collecting larger airborne particles and that is replaceable for each surgical procedure. In that way, a single main smoke filter cartridge module could be used for multiple surgical procedures by simply replacing the pre-filter assembly between each use.
It would further be desirable to provide a means for generating an accurate accumulated filter usage signal that could be used by operating room personnel during surgical procedures to quickly and easily ascertain the usable filter life remaining. Preferably, the accumulated filter usage signal would be an enhanced hybrid of the above-noted strict timer based and strict pressure differential based systems so that none of the usable filter life is wasted and to enable the system to be used over a wide range of vacuum air flow rates without erroneous filter life readings.